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Roots

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An \scriptstyle n \,th complex root (root of degree \scriptstyle n \,) is one of the \scriptstyle n \, complex solutions of

z^n = a,\quad n \in \N^+,\, a,\, z \in \C. \,

Contents

Real roots

An \scriptstyle n \,th real root (root of degree \scriptstyle n \,) is one of the real solutions of

x^n = a,\quad n \in \N^+,\, a,\, x \in \R. \,

If \scriptstyle n \, is an even positive integer, then the two real roots are

x = \pm \sqrt[n]{a}, \,

while if \scriptstyle n \, is an odd positive integer, then the single real root is

x = \sqrt[n]{a}. \,

Surds

A surd is an algebraic irrational root, e.g. \scriptstyle \sqrt[3]{2} \, is a cubic surd. The quadratic surd \scriptstyle \sqrt[2]{27} \,=\, 3 \, \sqrt[2]{3} \, is a mixed surd (i.e. a rational number multiplied by a surd).

See also

Hierarchical list of operations pertaining to numbers [1] [2]

0th iteration
1st iteration
  • Addition, S(S(... s times ...(S(n)))), the sum n+s
  • Subtraction, P(P(... s times ...(P(n)))), the difference n-s
2nd iteration
3rd iteration
4th iteration
5th iteration
6th iteration
7th iteration
8th iteration
  • Octation (d as "dimension", b as "base", n as "variable")
    • Octa-powers, n^^^^^(n^^^^^(... d times ...(n^^^^^(n)))), written n^^^^^^d or n↑↑↑↑↑↑d
    • Octa-exponentials, b^^^^^(b^^^^^(... n times ...(b^^^^^(b)))), written b^^^^^^n or b↑↑↑↑↑↑n
  • Octation inverses

Notes

  1. HyperoperationWikipedia.org.
  2. Grzegorczyk hierarchyWikipedia.org.

Notes

Retrieved from "http://oeis.org/wiki/Roots"
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